Dear mathseek,

by B look at the first and the 4th row.

C = a*e*d

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- December 20th 2008, 12:33 AM #1

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## determinantQnine

find the determinant of the matrices below by inspection.give reson in each case.

B=

row1 2 7 -3 1

row2 0 3 7 4

row3 3 5 -12 1

row4 4 14 -6 2

C=

row1 a b c

row2 0 e f

row3 0 0 d

D=

row1 3 0 0

row2 0 -2 0

row3 0 0 -1

how to do it by inspection?

- December 20th 2008, 02:00 AM #2

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- December 20th 2008, 02:04 AM #3

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- December 20th 2008, 02:34 AM #4

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- December 20th 2008, 02:59 AM #5

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row 1 is 2 times row 4, hence matrix is singular do det =???

C=

row1 a b c

row2 0 e f

row3 0 0 d

D=

row1 3 0 0

row2 0 -2 0

row3 0 0 -1

CB